1. Field of the Invention
The invention relates to an X-ray apparatus, comprising a film cassette which is displaceable in the loading direction in a carriage, a device for fixing the cassette position perpendicularly to the loading direction, two respective pairs of guide rollers which are arranged so as to be off-set with respect to one another in the loading direction on the apparatus and on the carriage, respectively, and independently controlled motor drives which act on the film cassette via a traction means guided via the rollers, the traction means sections between the rollers on the carriage and the rollers on the apparatus extending parallel to one another.
2. Description of the Prior Art
An X-ray apparatus of this kind is known from DE-AS 22 26 473. Therein, a first electric motor acts on one of the guide rollers, thus displacing the film cassette perpendicularly with respect to the loading direction. The displacement of the cassette carriage in the loading direction is realised by way of an additional traction means loop which is guided via two guide rollers which are arranged so as to be off-set in the loading direction with respect to one another, and one of which can be driven by a second electric motor. For an X-ray exposure, the carriage with the film cassette must be displaced a comparatively long distance from the parking position to the exposure position. The displacement of the cassette in the direction perpendicular to the loading direction, necessary in the case of an X-ray exposure with a vertical sub-division of the exposure format, however, is comparatively short; moreover, this displacement does not concern said carriage because the displacement of the carriage to the exposure position and the possibly required displacement of the film cassette in the carriage must take place at least substantially simultaneously, so that the second electric motor must have a substantially higher power rating than the first electric motor.